Threat Bulletin 0401: HTTP/2 rapid reset against a ticketing platform in the Benelux

On Sunday 4 September 2022 at 19:27 UTC, a HTTP/2 rapid reset targeted a ticketing customer in the Benelux. The attack peaked at 541.2 million requests per second and lasted 12 minutes. Traffic originated from 2193 autonomous systems in 105 countries, predominantly misconfigured open reflectors.

Timeline

The attack was preceded by no stated motive. Request rates on the targeted routes exceeded their hourly baseline by a factor of 792 within 20 seconds. The risk score of participating clients crossed the challenge threshold automatically and proof-of-work difficulty rose with origin load.

What the customer saw

A brief increase in p99 latency of 129 ms during the first minute, then normal service.

Recommendations

• Keep origin IPs out of public DNS history.
• Enable authenticated origin pulls.
• Review allow-listed partner ranges quarterly.